Boron hydrocyanations

Answer (a) hydrocyanic acid (b) boron trichloride (c) iodine pentafluoride ... 

With his colleague Louis-Jacques Thenard (1777-1857), Gay-Lussac did considerable work with electrochemistry to produce significant amounts of elemental sodium and potassium, highly reactive and useful substances that were used to isolate and discover the element boron. Gay-Lussac also completed extensive studies of acids and bases and was the first to deduce that there were binary (two element) acids such as hydrochloric acid (HC1) in addition to the known oxygen-containing acids like sulfuric acid (H2S04). Additionally, he was able to determine the chemical composition of prussic acid to be hydrocyanic acid (HCN) and was considered the foremost practitioner of organic analysis. 

All the reactions of the hydrocyanation process are catalyzed by zero-valent nickel phosphine or phosphite complexes. These are used in combination with Lewis acid promoters such as zinc chloride, trialkyl boron compounds, or trialkyl borate ester. The ability of the precatalyst to undergo ligand dissociation... 

A highly anti-selective hydrocyanation of (7 )-jV-Boc-2, 2-dimethylthia-zolidine-4-carbaldehyde (Gamer s aldehyde) with hydrogen cyanide in the presence of a Lewis acid has been reported [78]. In the initial study, we applied the procedure to the synthesis of anti-O-TMS cyanohydrin 23. However, the cyanosilylation of 22 in the presence of Lewis acid such as zinc iodide (Znl2), zinc bromide (ZnBr2) or boron trifluoride (BFy) diethyl ethcrate was problematic, leading only to traces of 23. 

Table 16.3. Selectivities for formation of the linear dinitrile from nickel-catalyzed hydrocyanation of 4-pentene nitrile in the presence of a series of boron Lewis acids.

Hydrogen cyanide —, elimination of — s. De-hydrocyanation Hydrogen fluoride/boron fluoride 16, 833 Hydrogen halide acceptor, formamide as — 16,174 Hydrogen iodide 16, 570, 627, 983 17,18,32,119 Hydrogenolysis (s. a. Hydrocarbons, Replacement by hydrogen)... 

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